2131638661 has 2 divisors, whose sum is σ = 2131638662. Its totient is φ = 2131638660.

The previous prime is 2131638637. The next prime is 2131638727. The reversal of 2131638661 is 1668361312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2070705025 + 60933636 = 45505^2 + 7806^2 .

It is a cyclic number.

It is not a de Polignac number, because 2131638661 - 2¹⁵ = 2131605893 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2131638661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2131638161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1065819330 + 1065819331.

It is an arithmetic number, because the mean of its divisors is an integer number (1065819331).

Almost surely, 2^2131638661 is an apocalyptic number.

It is an amenable number.

2131638661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2131638661 is an equidigital number, since it uses as much as digits as its factorization.

2131638661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 37.

The square root of 2131638661 is about 46169.6725242881. The cubic root of 2131638661 is about 1286.9782166429.

Adding to 2131638661 its reverse (1668361312), we get a palindrome (3799999973).

The spelling of 2131638661 in words is "two billion, one hundred thirty-one million, six hundred thirty-eight thousand, six hundred sixty-one".